I have it set-up so the choice is between 3 options (small, medium and large items). No matter which option is chosen for shipping, PayPal only ever has small items shipping.

I am thinking this is due to the way the shipping is defaulting back to small items, no matter what option is chosen.

For instance, if I choose Large Items shipping, the the total cost shows the correct amount, but the shipping option reverts back to Small Items shipping (by default).

Ideally I would like the shipping option to remain on the option specified, and not to default back to Small Item shipping, can this be done?

I ask because no matter what shipping option is chosen on the site, PayPal only ever charges for small items shipping (which I believe is down to the shipping box defaulting back to Small Items shipping, instead of remaining on the shipping option chosen.)